Method of manufacturing flare end tubes



Feb. 21, 1933. A. T. KVARNSTROM METHOD OF MANUFACTURING FLARE END TUBES Filed May 1, 1929 0 8 Ar 2 m HHHHM. g \1 V .01 .ll IH I L Illlm'l llll ll-ll 7W 4 m z w Z Ills III lilil Ill m m P HH M I ll INVENTOR. flf/rcc/ T fiarnstrom ATTORNEYJ Patented Feb. 21 1933 UNITED STATES ALFRED T. KVARNSTROM, OF DETROIT, MICHIGAN METHOD OF MANUFACTURING FLARE END TUBES Application filed May 1, 1929. Serial No. 359,467.

My invention relates to an improved flare end tube and to improvements in the method of manufacturing or forming an improved flare end tube or flaring the same.

An important object is to provide an improved method of forming an improved flare end tube wherein the flare end is so reinforced that it is strengthened and protected against breakage, rupture, or the like, and a rigid flare end is provided.

A further object consists in so flaring the end of the tube thatthe end is protected during the flaring operation and the reinforcement is secured and aflixed to the end to be flared during the flaring operation.

Other objects, advantages, and meritorious features of my invention will more fully appear from the following specification, appended claim, and accompanying drawing,

wherein,-

Fig. 1 is a sectional view through a tube to be flared showing the tube and reinforcing end thimble separated.

Fig. 2 is a View similar to Fig. 1 showing a modified form of reinforcing thimble.

Fig. 3 is a view similar to Fig. 1 showing a second modified form of reinforcing thimble.

Fig. 4 is a sectional view taken on the same line as Fig. 1 showing the reinforcing thimble arranged over the end of the tube and at the beginning of the flaring operation.

Fig. 5 is a sectional view taken on the same line as Fig. 4 showing the tube and thimble 5 following the flaring operaion.

Fig. 6 is a view taken on the same line as Fig. 5 showing the modified form of thimble shown in Fig. 2 secured to the tube.

Fig. 7 shows a metal tube with the thimble 16 inserted thereover at the beginning of the flaring operation.

In flaring the end of the metal tube the metal at the end to be flared is so drawn during the flaring operation that it is weakened to the point that breakage or rupture 1s likely to result and it is incapable of withstanding substantial strains or pressure. My invention relates to so forming or flaring the end of a metal tube that the resulting flared end Will possess substantial strength and to accomplish this I provide a reinforcement therefor which is secured to the tube and affiXed about the flared end during the flaring operation. This reinforcement and the method of its attachment to the tube is of the general character and follows the general plan here set forth but may be embodied in slightly different modified constructions.

In Figs. 1 to 4. of the drawing there is illustrated a metal tube 10 of uniform dianieter, one end of which it is desired to flare outwardly. I provide a reinforcement for this flared end in the form of a metal thimble.

These thimbles are indicated as 12, 1 1 and 16, in Figs. 1 to 3 respectively. In Fig. 1 the thimble has a pair of spaced apart walls of substantially equal length, while in Fig. 2 the outer wall extends downwardly substantially upon the inner wall forming a long skirt, and in Fig. 3 the original thimble is shaped in the form of a cup. In each case the metal thimble is arranged over the end of the tube 10 as indicated in Fig. 4.

In flaring the end of the tube, a die 18 is provided which has a flared portion 20 terminating in an axially projecting centering portion 22. If the thimble 12 is used it will be seen that insertion of the die into the thimble will flare the end of the tube and the thimble outwardly, as shown in Fig. 5, crimping the thimble securely about the flared end of the tube and reinforcing the flared end of the tube.

If the thimble 14 is employed the result 1 will be as indicated in Fig. 6 with the skirt of the thimble extending along the uniform diameter portion of the tube away from its flared end.

If the thimble 16 is employed the portion 2 1 of the die enters the aperture 17 of the thimble 16, as shown in Fig. 7 centering the die with respect to the thimble, and pressure exerted thereon toward the tube forces the top of the thimble 16 into the tube 10 and..95 against the side wall thereof in a manner similar to that of the thimble 12 in Fig. 1, and further pressure flares the end of the tube and the thimble outwardly as hereinabove described. 131

What I claim is:

That method of forming a flare end tube comprising placing a cup-shaped thimble over the portion of the tube to be flared extending downwardly along the outside of the tube and then forcing the top of the thimble into the tube and flaring the thimble covered end of the tube outwardly binding the thi1n ble thereabout.

In testimony whereof, I, ALFRED T. KVARN- sTRoM, sign this specification.

ALFRED T. KVARNSTROM. 

